Of course there’s a caveat: to get results from such short workouts, you have to be willing to push yourself hard, Gillen says. Numerous studies have shown that intense interval training protocols can get results from relatively short workouts. Gillen and her colleagues at McMaster University wanted to know just how short that workout can be.
The answer, from a study they did in 2016 was: one minute of intense exercise in a workout lasting 10 minutes total (including the warm up and cool down), three times per week.
Gillen’s team randomly assigned participants to three groups. One pedaled an exercise bike at a moderate level of effort for 45 minutes, three times per week. A second group did thrice weekly the 10-minute workouts that included three segments of 20 seconds of all-out sprint cycling, for a total of one high-intensity minute each workout. (The rest of the time was easy spinning.) A third group served as a control and did nothing.
After 12 weeks, both exercise groups had improved their insulin resistance and also increased their fitness (as measured by their capacity to use oxygen during exercise) by about 19 percent. The gains were similar between the groups, even though the group doing short workouts with high intensity intervals had spent only about 22 percent as much exercising as the group doing traditional longer workouts.
Similarly, a 2020 study by researchers at the University Hospital Erlangen in Germany put 65 sedentary, obese volunteers on an exercise program consisting of warming up on an exercise bike for two minutes, then doing five one-minute bouts at 80 to 95 percent of their maximum heart rate, with one-minute easy pedaling recovery periods in between. With the three-minute cool down, the total workout time was 14 minutes, and these workouts were performed twice a week for 12 weeks. Participants in this simple 28-minute-per-week program improved their VO2max scores (a measure of cardiovascular fitness), and they also reduced their blood pressure and waist circumferences.
The improvements in cardiorespiratory fitness seen in these studies is a strong predictor of reduced morbidity and mortality risk, and are especially important for people at risk of developing diabetes, or other metabolic conditions, says Louise de Lannoy, an exercise physiologist at Children’s Hospital of Eastern Ontario Research Institute.
Still, the intensity required to achieve the benefits of short workouts does take some gusto.
“Especially for someone who’s been sedentary, getting up to that maximal effort can be very challenging,” de Lannoy says. This level of intensity feels all out — you’re going as hard as you possibly can. “But it also can be fun. It’s quick, little bit of pain, you get a rest and do it again,” de Lannoy says.
Another 2020 study confirmed that some people do find these hard interval exercise programs enjoyable enough to continue. Exercise scientist Matthew Stork of the University of British Columbia and his colleagues brought a group of previously sedentary adults into the lab to do short workouts with high intensity one-minute intervals on an exercise bike. Participants reported that the high intensity bouts were hard, but some of them enjoyed them enough that they continued to do them after the study.
“I’ve tried these workouts myself and it takes a lot of self-coaching yourself to get up to 90 percent of your max,” de Lannoy says. That said, if you do a workout with repeated hard intervals and a short rest period, they’re likely to get harder as you go, so even if your first interval is only 60 percent of your max, by the third or fourth one you might be closer to 90 percent, she says. If you don’t have an exercise bike, briskly climbing some stairs is another good way to get your heart rate up quickly.
“A good rule of thumb is to build over time,” de Lannoy says. “You might start at 60 to 70 percent of your heart rate max, and try to increase that over time and build toward 90 percent.”
Short workouts can build muscle
Cardio workouts aren’t the only ones going shorter. Studies also show that you can make big strength gains from brief resistance training workouts.
A 2019 study published in the journal Medicine & Science in Sports & Exercise investigated the correlation between the number of sets of exercises performed and strength gains.
Participants in the study did a similar routine of seven strength-training exercises, three times a week. One group did five sets of the exercise each session, another group did three sets, and the third group did only a single set of exercises per workout. By the end of the eight-week program, all groups had achieved similar improvements in muscle strength and endurance. Doing three or five sets per workout increased the amount of time people were exercising, but it didn’t result in bigger gains. (The group that did the longer workouts did make bigger increases in muscle size in thigh muscles and elbow flexors, however.)
There is often skepticism around the idea of short workouts, because they have been portrayed as gimmicky, says James Steele, associate professor of sport and exercise science at Solent University in England and principal investigator at the London-based UKActive Research Institute. But he says that if you’re aiming to get stronger, you do not necessarily need to spend lots of time in the gym or do a lot of reps. Instead, what’s important is doing the exercise until you attain “momentary muscular failure” — the point at which you can’t complete another rep. Steele was part of a research team that published evidence-based resistance training recommendations calling for a single set of eight to 12 repetitions to momentary muscular failure.
The Dutch company Fit20 runs franchise fitness studios that specialize in this “minimal effective dose” approach to workouts. It has a data set of almost 15,000 people who had participated in their program over a seven-year period, and Steele’s team recently used it to model people’s strength progression over time. The team found that Fit20 members were making substantial strength gains (on the order of 30 to 50 percent gains over the first year), despite doing a minimal amount of training: a single set of four to six repetitions of six exercises, once per week.
The study shows that you can make meaningful improvements in your muscle strength in just one short workout a week, but Steele says he recommends that people aim for twice a week so that if they miss a session, they remain on track.
The minimal effective dose approach isn’t just for average folks. Studies done by Patroklos Androulakis-Korakakis, a researcher at Solent University and a coach at StrongerByScience.com, a program offering science-backed strength training, show that it works for highly trained athletes, too. He conducted studies on serious powerlifters and found that they also make substantial strength gains while following a minimal effective dose plan.
Remarkably, the powerlifters in Androulakis-Korakakis’s studies who trained with at minimum dose approach ended up experiencing very little soreness. “They had very low soreness scores, one or less on a scale of one to five,” he says.
Androulakis-Korakakis says his research suggests that “Hey, you could be doing much less than you’re currently doing and see great results.” A minimalist approach might not give the absolute best results, but it gives a lot more bang for the buck, especially when you consider the trade-offs of time and recovery, he says.
Turning to shorter workouts is not just a way to save time. It also can help you continue to make fitness gains even when life gets in the way.
“Let’s say you have exams coming up or your job is picking up and you only have a couple of hours per week” to exercise, Androulakis-Korakakis says. Instead of feeling like your strength and muscle mass will suffer, turning to a minimum dose approach can help you continue building your fitness.
“It’s hard to argue that you don’t have 10 or 15 minutes that you can find. That’s just not checking your email one more time or getting off social media,” de Lannoy says.
